Roll forming apparatus for sheet metal

ABSTRACT

A pair of forming rolls for forming an outwardly opening return bent channel formation at an end of a cylindrical sheet metal workpiece such as a duct. The channel is formed in two operations. The workpiece is first inserted between the forming rolls to full depth against a gauge, the rolls are closed, and a relatively open V-shaped formation is formed. The rolls are then released and the workpiece is partially withdrawn until the apex of the V-shaped formation registers with a narrow annular groove in one roll and the rolls are again closed, whereby a plain cylindrical formation on the other roll engages the outer ends of the V formation and forces the same into the annular groove to complete a relatively narrow U-shaped return bent formation.

United States Patent [56] References Cited UNITED STATES PATENTS |72]Inventors Lawrence L. Hock Snyder;

4 )4 5X5 4 (4 WSW 2N2 2 7 PATENTED Jun l isn IN VENTO/e5 R. 5 KJS W CSAN ON@ 2 HMA o LQK im EE Mcm ENN REE RH AW@ LC& Y DD l RoLL EoRMrNGAPPARATUS Fok SHEET METAL BACKGROUND OF THE INVENTION This inventionrelates to rolls for forming sheet metal and, more particularly, to apair of cooperating rolls for forming return bent annular flanges at theends of cylindrical sheet metal duct members and the like.

In fabricating sheet metal duct work and like sheet metal structures, itis commonly required to produce return bent flange formations at theends of cylindrical sheet metal duct members. Since the return bentflange formations arecommonly for the purpose of interfitting with sheetmetal portions of connecting duct work the required space between thereturn bent flanges approximates the thickness of the sheet metal usedin the duct work and is accordingly too narrow to admit a male formingmember of practicable thickness in the final formation of such returnbent flanges.

It is accordingly necessary, in prior art roll forming methods, toproduce such return bent flange formations in a succession of formingsteps employing different sets of fonning rolls. In order to do this itis veither necessary to set up two or more roll forming machines withsuccessively employed sets of forming rolls or, where several rollforming machines are not available, it is necessary to perform a firstforming operation with a given set of forming rolls on a number ofworkpieces, and then remove the first forming rolls and install secondforming rolls to perform the second forming operation on the successionof-workpieces.

SUMMARY OF THE INVENTION The present invention provides a pair offorming rolls which are so contoured that a workman may introduce asheet metal cylindrical or other structure between the forming rolls andagainst a stop, the forming rolls being then open or separated in amanner well known in this art, then close the rolls and rotate the sameto form a relatively open V-shaped formation at an end of the sheetmetal structure. The rolls are then opened to release the workpiecewhich is then partially withdrawn by the workman to place it in suchposition that the relatively open V-shaped formation rests partially inor against a narrow channel formation in one of the rolls.

The rolls are then again closed and the registering periphery of theother roll forces a beginning portion of the` apex of the open V-shapedformation into the relatively narrow annular channel to close suchportion and thus form a return bent formation having a relatively narrowspace between the adjacent flanges of the return bent formation. Therolls are then rotated in the usual manner whereby successive portionsofthe V- shaped channel formation are progressively forced into therelatively narrow groove formation in the aforesaid forming roll tocomplete the return bent formation at the end of 'the workpiece.

The contour of the mating rolls of the present invention is such thatthe two successive forming operations just described may be successivelyeffected, each without interference from portions of the forming rollsemployed in effecting the other of the forming operations.

BRIEF DESCRIPTION OF THE DRAWING The single FIGURE of the drawing is anenlarged vertical longitudinal section through one form of a pair offorming rolls constructed according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing the numerals land ll designate the upper and lower roll shafts of a conventional rollforming machine. In such machines one of the roll shafts, usually theupper one, may be swung upwardly to separate the rolls for introducingworkpieces therebetween and removing them when a roll forming operationhas been effected.

The principal roll component of the upper forming roll is designated l2and is mounted on a reduced extension 13 of upper roll shaft l0. Acylindrical member 14 forms an axial extension of upper forming roll l2and] has a reduced threaded portion l5 which threads into the outer endof reduced shaft extension 13 to retain principal upper roll componentl2 on extension 13. As will appear later herein, upper roll component l2comprises a first form roller and cylindrical extension 14 comprises asecond form roller.

The first form component of the lower forming roll is designated 20 andis mounted on a reduced extension 2l of lower roll shaft ll. A secondform component of the lower forming roll is designated 22 and has areduced threaded extension 23 which threads into the outer end of lowershaft 11 and thus retains the first form component 20 thereon. A shim 24is interposed between the facing end surfaces of roll components 20 and22 for a purpose which will appear later herein.

The workpiece prior to being formed by the novel roll-formingcombination of the present invention comprises a sheet metal cylinderhaving a plain end. The cylindrical workpiece is designated 25 in thefull and dotted line showings in the drawing. The full line showingillustrates the end ofthe cylinder after the first forming operationand. the dot and dash line showing illustrates the final form thereof.With the rolls separated, that is, with the upper roll shaft l0 and itsappurtenances raised from the lower roll shaft and its appurtenances,the plain end of the cylinder is broughtrinto abutment with what isknown as an apron gauge 27.

The upper first forming roll 12 has an annular flange 28 and an adjacentannular groove 29. The lower first forming roll 20 is formed with acomplementary annular groove 30 and an annular flange 3l. Accordingly,when upper roll shaft l0 is lowered the engaged or beginning portion ofthe cylindrical workpiece 25 is brought to the form illustrated infulllines in the drawing. As the roll shafts l0 and 1l are then rotated,either by power or manual means, the illustrated cross section shown infull lines is formed about the entire end of cylinder 25.

The rolls are then again separated and the workman merely withdraws theworkpiece partially until the interior bead for mation 32 of theworkpiece registers with an annular recess 33 which is formed by theouter end of roll component 20 and a flange 34 formed on the second formcomponent 22 of the lower forming roll. When roll shaft 10 is againlowered to working position the bead formation .32 is forced into recess33 and assumes the form illustrated in dot and dash lines wherein aUshaped formation with parallel sidewalls is produced, this being thedesired final shape of the end of the cylindrical sheet metal workpiece.

This U-shaped formation is require-d in various widths due to varyingguages of the sheet metal workpiece and varying thicknesses of therelated duct work with which the U-shaped formation is to be engaged.Accordingly, various shims such as the one illustrated at 35 in thedrawing engage between first form roll component 20 and second form rollcomponent 22 and by varying the thickness of shim 3S the width of recess33 may be correspondingly varied.

It will be noted in the drawing that roll 14 will assume a lowerposition in the second form operation than in the illustrated first fonnoperation since roll 14, in the second form, will approach within ametal thickness of the outer periphery of flange 34. It will further benoted that the general diameter of the cylindrical workpiece 2S isnearly the same as the internal diameter of the return bent formation sothat the effective general internal area of cylinder 25 is not reducedby the return bent formation.rAccordingly, the workpiece tapers inwardlyfrom the radius which is formed over flange 3l to the general diameterof the main body of the cylindrical workrece. p A preferred embodimentof the present invention has been described and illustrated herein butit is to be understood that numerous modifications may be made withoutdeparting from the spirit and scope of the invention.

We claim:

vrolls and a complementary annular flange on the other roll to producean open return bent formation along the edge of the workpiece, thesecond pass formations of said grooved roll comprising a narrowerU-shaped annular groove, a peripheral portion of the flanged roll beingadapted to engage the outer ends of the return bent formation of theworkpiece and force the same into said U-shaped groove to produce areturn bent formation with a relatively narrow space between the wallsthereof.

2. A pair of forming rolls in accordance with claim l wherein therelatively open annular groove and the complementary annular flange aregenerally V-shaped.

3. A pair of forming rolls in accordance with claim l wherein said openreturn bent formation has an external radius approximately one-half thewidth of said V-shaped annular groove.

4. A pair of forming rolls in accordance with claim 2 wherein said openreturn bent formation has an external radius approximately one-half thewidth of said V-shaped annular groove.

5. A pair of forming rolls in accordance with claim l wherein said oneroll has a reduced diameter portion outwardly of said annular groove andsaid other roll has an increased diameter portion outwardly of saidannular flange whereby said workpiece is provided with a taperingenlargement between the workpiece proper and the return bent formationat the end thereof.

6. A pair of forming rolls in accordance with claim 2 wherein said oneroll has a reduced diameter portion outwardly of said annular groove andsaid other roll has an increased diameter portion outwardly of saidannular flange whereby said workpiece is provided with a taperingenlargement between the workpiece proper and the return bent formationat the end thereof.

7. A pair of forming rolls in accordance with claim 5 wherein saidU-shaped groove is formed in the reduced diameter portion of said oneroll and the increased diameter portion of said other roll engages thereturn bent formation of the workpiece to force the same into saidU-shaped groove.

1. A pair of forming rolls for effecting successive roll formingoperations along an edge of a sheet metal workpiece, said rolls beingrotatably supported at one end thereof, one of said rolls being movableaway from the other for introducing the edge of a workpiecetherebetween, said rolls having first and second pass peripheralformations with the first pass formations toward the supported ends ofthe rolls and the second pass formations outwardly thereof, said firstpass formations comprising a relatively open annular groove in one ofsaid rolls and a complementary annular flange on the other roll toproduce an open return bent formation along the edge of the workpiece,the second pass formations of said grooved roll comprising a narrowerUshaped annular groove, a peripheral portion of the flanged roll beingadapted to engage the outer ends of the return bent formation of theworkpiece and force the same into said U-shaped groove to produce areturn bent formation with a relatively narrow space between the wallsthereof.
 2. A pair of forming rolls in accordance with claim 1 whereinthe relatively open annular groove and the complementary annular flangeare generally V-shaped.
 3. A pair of forming rolls in accordance withclaim 1 wherein said open return bent formation has an external radiusapproximately one-half the width of said V-shaped annular groove.
 4. Apair of forming rolls in accordance with claim 2 wherein said openreturn bent formation has an external radius approximately one-half thewidth of said V-shaped annular groove.
 5. A pair of forming rolls inaccordance with claim 1 wherein said one roll has a reduced diameterportion outwardly of said annular groove and said other roll has anincreased diameter portion outwardly of said annular flange whereby saidworkpiece is provided with a tapering enlargement between the workpieceproper and the return bent formation at the end thereof.
 6. A pair offorming rolls in accordance with claim 2 wherein said one roll has areduced diameter portion outwardly of said annular groove and said otherroll has an increased diameter portion outwardly of said annular flangewhereby said workpiece is provided with a tapering enlargement betweenthe workpiece proper and the return bent formation at the end thereof.7. A pair of forming rolls in accordance with claim 5 wherein saidU-shaped groove is formed in the reduced diameter portion of said oneroll and the increased diameter portion of said other roll engages thereturn bent formation of the workpiece to force the same into saidU-shaped groove.